Ground detector



Dec. 6, 1927,

c. c. VAN VOORHIS GROUND DETECTOR Filed Dec. 1:3, 1919 i INVENTOR ('lelus CYI IPIOI? Valzl m'lzz'j WITNESSES i AT bRNEY Patented Dec. 6, 1927.

UNITED STATES 1,651,423 PATENT OFFICE.

CLETUs CLINTON VAN VOORHIS, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

GROUND nnrnc'ron.

Application filedDecember 13, 1919. Serial No. 344,611. I

My invention relates to ground detectors and particularly to vacuum-tube ground detectors.

One object of my invention is to provide an indicatin device that shall be adapted to indicate W en any one of the bus-bars, to which it is connected, becomes grounded.

Another object of my invention is to provide an indicating device, of the above indicated character, that shall be visible from a distance.

A further object of my invention is to provide an indicating device, of the above indicated character, that shall be compact and simple, and inexpensive to construct.

In practicing my invention I provide a glass receptacle comprising a central bulb and a plurality of radially disposed bulbs that are connected to the central bulb by tubes. An electrode is sealed in each bulb. The electrode in the central bulb is connected to the ground and each of' the remaining electrodes is connected to a point on a corresponding bus-bar insulator that is immediately beyond the section adjacent the supporting framework. The insulators that support the bus-bars comprise pluralities of sections that are so disposed between the bus-bars and the supporting frame as ,to constitute, in effect, pluralities of condensers connected in series therebetween. Since the supporting frame is normally grounded, the insulator sections that are adjacent the frame constitute condensers connected. between the electrodes of the central and the radial bulbs, respectively.

The gas is withdrawn from the receptacle in order to create a low-pressure partial vacuum therein. The receptacle is, in effect, a plurality of Geissler tubes that have a common bulb and extend radially therefrom. Various gases may be used for different colored indications that may be effected in the several tubes by the condenser discharge of the insulator sections connected thereto. Normal conditions are indicated by a glow elfected by discharges through the tubes. 1

A ground on any bus-bar eliminates the potential gradient across the insulator that supports the bus-bar and, therefore, the po tential becomes the same on both sides of the section that is used as a condenser for effecting discharges through the tube. The

that is affected may thus be readily indicated by the absence of glow in the tube that is connected thereto.

Figure l is a front' elevational view of a ground detector embodying my invention; Fig. 2 is a side elevational view, of the detector shown in Fig. 1, and Fig. 3 is a diagram showing the connections of the ground detector.

A ground detector 1 comprises a central bulb 2 and a plurality of radially disposed bulbs 3, 4, and 5, connected thereto by a plurality of tubes 6, 7 and 8. Electrodes 9, 10, 11 and 12 are sealed in the glass wallsof the respective bulbs 2, 3, 4 and. 5. The central bulbelectrode 9 is connected to ground 13 and the electrodes 10, 11' and 12 of the radially disposed bulbs 3, 4 and 5 are connected to points 14, 15 and 16 between the ends of the insulators 17 18 and 19, respectively. The insulators 17, 18 and 19 support the bus-bars 20, 21 and 22, respectively of a polyphase circuit, and are mounted on a supporting framework 23, that is connected to the ground 13.

Normal conditions in the circuit are indicated b a marked glow in the tubes 6, '2' and 8 t at join the central bulb 2 aid the radially disposed bulbs 3, 4 and 5. This glow being caused by the drop in potential across the portions of the insulators between the points 14, 15 and 16-and the ground and, consequently, across the respective tubes. That is, portions of the insulators constitute condensers across which the tubes are con nected. A ground on any bus-bar, such as might occur through a broken and grounded line or through a broken insulator will destroy the potential gradient across'the insulator that supports the corresponding bus bar, by equalizing the bus-bar and the framework potentials. The absence. of potential difference across the insulator sections 24, 25 and 26 precludes any glow in the tubes connected thereacross. The faulty bus-bar or line may thus be readily indicated.

Although I have shown only one form of ground detector embodying my invention, I do not wish to be limited to the structure shown, as various modifications may be made therein Without departing from the spirit' and scope of the invention, as set forth in the appended claim.

I claim as my invention:

In an alternating-current system, the combination with the conductors thereof and insulating members for the conductors, of a ground-detector comprising a vacuum receptacle having a central bulb and a plurality of bulbs joined thereto, a plurality of electrodes sealed in the respective bulbs, said electrodes being so electrically disposed as to include a portion of the respective in sulating members between the central electrode and the respective radially disposed electrodes.

In testimony whereof, I have hereunto subscribed my name this 8th day of December 1919.

CLETUS CLINTON VAN VOORHIS. 

